Warm air furnace



my 3 w34.. Q KEEFE 1,964,381

WARM AIR FURNACE Filed Oct. l2. 1932 2 Sheets-Sheet l BYl v@ JEYK J. O. KEEFE WARM AIR FURNACE juy 3, E934.

Filed Oct. 12. 1932 2 Sheets-Sheet 2 Patented July 3, 1934 UNHTED STATES PATENT FFICE 2 Claims.

My invention relates to improvements in Warm air furnaces, and the warm air heating industry is in need of a plant which exceeds any of the currentdesigns in eflciency, cleanliness, and ease to the owner in maintenance and operation; but whose Erst cost and maintenance cost is no greater than that of the average plant of today.

The object of my invention is to fulrlll this need to a far greater degree than has ever been achieved before. The general design which I have executed in my invention dilfers radically in so many respects from the existing designs that it cannot be classed as a mere improvement, but must be classed as a wholly new and original design.

With this object in view, my invention consists of a warm air furnace embodying novel features of construction and combination of parts for service, substantially as described and claimed, and as shown in the accompanying drawings, in whichz Fig. 1 is a vertical section through complete assembly of furnace, casing, and water pan,

Fig. 2 is a right side view of the furnace and water pan, including the lower casing ring, with the air casing removed,

lig. 3 is a vertical section through the junction point of the nre box section of the furnace and the combustion chamber section,

Fig. 4 is a left side view of the junction point of the fire box section of the furnace and the combustion chamber section,

Fig. 5 is a vertical section through the junction point of the ash pit section of the furnace,

Fig. 6 is a right side view of the junction point of the ash pit section of the furnace and the iire box section of the furnace,

Fig.' 7 is a top View of the complete assembly of the furnace, casing, and water pan with many of the details of the furnace omitted,

Fig. 3 is a front view of the complete assembly f the furnace, casing, and water pan with many of the details of the furnace omitted.

rIhe furnace is constructed in three separate sections, namely: the ash pit section, the re box section, and the combustion chamber section.

Referring by numeral to the drawings in which the same numerals of reference denote like parts in all the views of said drawings:-

The ash pit section consists of the walls l, and the angles 2, 3 and 4, which are fastened to the Walls l.

The angles 2 and 3 rest on the brick walls 5 and 6, while the angle 4 rests on the floor. The

re box section rests on these angles and is secured to the ash pit section by bolts and nuts 7.

The re box section consists of the walls 8; the passage way to the ash pit door 9; the re brick supports 11, 12 and 13, which are fastened toI the walls 8; the nre bricks, 14; the grate supports, 15 and 16 which are fastened to the walls, and the removable grate support 17 which is secured to the grate support 15 by the bolts and nuts 18; the stationary grate 19 and the worm grates 20 and 21; and the level bars 22, 23, 24 and 25.

The Walls 26 of the combustion chamber section rest on these bevel bars as shown in Figures 3 and 4.

Besides the Walls 26, the combustion chamber consists of the passage way to the rire door 27; the passage way to the clean out door 28; the air tubes 29, which are secured to the Walls 26 by nuts 30; the main smoke pipe 31 with damper 32 (consisting of rod 33, weight 34, and chain 35) therein; the connecting smoke pipe 36; the radiator pipes 3'7, the clean out pipe 38; and the union box 39.

The union box 39 is supported by an angle 40 which is fastened to the combustion chamber Wall 26. The plate 41 which lies on the bottom of the union box 39 provides a sliding surface for the damper 42. Two rods 43 and 44 are fastened to the damper 42 at one end and to the bar 45 at the other end. Springs 46 and 4'7 placed around the rods 43 and 44 are restrained at one end by the nange of the damper 42 and by the bracket 43 at the other end. The bracket 48 is fastened to the rear wall of the union box. The clean out cap 49 nts over a collar of the rear union box Wall. A rod 50 is screwed into the bar 45 and is linked to rod 51 which is in turn linked to rod 52. Rods 51 and 52 are supported by bars 53, 54 and 55, which are fastened to the staves 73.

The water pan 56 rests on the combustion chamber section. It is secured in place by small angles 57. The water pan is supplied by the pipe 58. The water level in the pan is governed by the Water glass 59.

60 is the shaker bar and ts on the square lugs of the worin grates as shown in Figures 9 and 10.

The connection of the door frame to the passages is made air tight by flanges 62. The clean out door 63, the nre door 64, and the ash pit door are hinged to the door frame 61. The ash pit door contains the draft 66 and two coverings 67 and 68 for the shaker bar holes.

The casing consists of two parts: the casing skeleton and the casing sheets. The casing skeleton contains the lower casing ring 69, the middle casing rhig 70, the upper casing ring 71, the bar braces '72, the corner staves '73, and the center staves 74. The casing sheets are the lower casing sheet 75, the upper casing sheet 76, the air guides 77, and the bonnet 78. The upper and lower casing sheets have fastening lugs 79. The air guides are fastened to the corner staves 73. The upper casing sheet is cut to slip over the union box bracket and the clean-out, and also cut to fit closely to the rear side of the union box as shown in Figures l5 and 18.

The spaces 8O and 8l on each side of the brick walls 5 and 6 provide for under floor cold air duct entrances into the plant.

The elements of my plant which make for greater efficiency over existing warm air heating plants are as follows:

The amount of heating surface is not so essential to the plants efficiency as is the location of the heating surface in relation to the hottest part of the burning fuel-the flame. The air tubes which cross the combustion chamber will be completely enveloped in the names, consequently the temperature of the tubes will be equal to that of the flames. Such a high teinperature and the relatively small cross-sectional area of each pipe will heat the air so much faster and cause such an increase in pressure that the volume of air passing into the rooms per unit of time will be increased approximately 100%.

This flame-contact will also greatly raise the number of B. t. ufs utilized from each pound of coal.

After the ire is well under way, the damper in the main smoke pipe is closed. This forces the smoke toward both sides of the combustion chamber, out the radiator pipes, down to the union box, up through the connecting pipe to the main smoke pipe, and then into the chimney. This relatively long smoke route within. the casing will minimize the heat losses that ordinarily go up the chimney. By compelling the smoke to leave the combustion chamber through two pipes instead of one the right and left sides of the chamber receive most of the heat. Ordinarily, because of the location of the cold air duct entrances and the greater amount of area relative to the rear end area of the chamber, most of the air which is to be heated will pass along the sides of the combustion chamber. Thus these radiator pipes cause the heat from the coal to be applied at the most useful places, the 'sides of the combustion chamber. The down draft induced by the slope of the radiator pipes will reduce the velocity of the smoke and gases, and consequently reduce the rate of combustion within the re box.

The air guides will divert the air toward the space between the radiator pipes and the cornbustion chamber. Thus the air will pass over the most highly heated surfaces, and there will be no chance that any air can escape into the warm air pipes without being properly heated.

The slope of that part of the bonnet to which the warm air pipes will be connected is perpendicular to the slope of the tubes in order to reduce resistance to the flow of the air. Another reason for this slope of the bonnet is to provide room enough for a person to pass under the pipes around the outside of the plant without necessitating the use of more than one elbow in the pipes.

When the warm grates are shaken there will be no lifting or disturbing of any part of the nre except the ashes which are in immediate contact with the grates. Therefore, hot coals or line green coal cannot filter through into the ash pit.

The rectangular shape of the rebox will assure very economical and satisfactory firing in moderate weather. A fire of full depth can be kept in the back part of the box. This will do two things: First, the location of the fire will compel the heat to travel over the longest possible path before it leaves the combustion chamber; second, the depth of the re will considerably decrease the rate of combustion as compared to the rate of combustion of a fire covering the whole grate area.

The required percentage of relative humidity (something seldom achieved in a warm air heating plant) can only be secured by a water pan with ample capacity to conform with the firing period (eight hours), suihcient evaporation per unit volume of air, and the water pan located such that the vapor will be carried into the rooms of the building. The above conditions are obtained in the best manner by placing the pan on top of the combustion chamber.

The elements of my plant which make for greater cleanliness over existing plants are as follows:

The ash pit is sunken in order to increase its volume and to make it possible for the pit to hold water. Thus the ashes will be simultaneously wetted down with the shaking of the grates. The steam and dust raised will be adequately taken care of, without the slightest chance of escape into the space outside the plant, by opening the union box damper and allowing these fine particles to pass out into the chimney by the way of the clean-out pipe, the union box, the connecting pipe, and the main smoke pipe.

The connection between the worm grate lugs and the shaker bar will be made dust tight by the collar on the shaker bar which seals the hole through the ash pit door.

The various junction points between the furnace sections, between the door frame and the passage ways, between the door frame and the casing, and between the casing and the union box are all constructed so as to be dust tight without the use of furnace cement; although, provision has been made for cement to be used at all these joints if necessary.

The slope of the top of the fire door passage will prevent smoke from puffing out the fire door when the fire is being replenished with fuel. The near-by and ideal location of the radiator pipe openings into the combustion chamber will also help to prevent smoke from puffing out the fire door.

The elements of my plant which make for greater ease in operation and in maintenance over existing plants are as follows:-

The ash pit will require emptying approximately one-half as many times as will the ordinary ash pit, because its volume has been approximately doubled by being sunken below the floor level.

The stationary grate will add considerable strength and stability to the re box.

The rectangular shape of the fire box whose width is only slightly larger than the width of the nre door makes possible very even firing with either coal or wood, easy cleaning of the fire (all nooks and corners can be reached), and easy building of the fire.

The casing skeleton makes it possible to remove the lower or upper casing sheets for cleaning or repairing the furnace without disturbing the bonnet and the warm air pipe connections to the bonnet.

If any cross air tube should burn out, provision has been made for its quick and easy removal and replacement by having these tubes secured to the combustion chamber walls by nuts.

If any section of the furnace should become defective, an entirely new furnace would not have to be purchased because of the three section construction of the furnace. Only the defective section would have to be replaced.

Not a particle of dust can escape outside the furnace during the cleaning of the soot from the radiator pipes and other smoke pipes. This is made possible only by such elements of the plant as the ideal location of the clean-out door, the down slope of the radiator pipes, the connecting pipe, the clean out opening in the union box, and the clean out pipe which connects di rectly to the ash pit.

A very convenient control of the union box damper from the front of the plant has been provided in the rod linkage, bracket, and springs as shown in Figure 7.

It will be noted that the fire or combustion chamber of my furnace is flared at its upper portion and that the surmounting drum has upper and lower inclined walls and straight side Walls and the effect of this is to cause a mingling or movement of the heat in the drum and its contact completely against the interior crossed pipes whose upper ends lead to and exit through said inclined walls of the drum, all of which insures the highest degree of heating efficiency.

I claim:

l. A warm air furnace, comprising a casing, a combustion chamber in the lower portion of said casing, a grate in the combustion chamber, a drum surmounting said combustion chamber, interior and exterior heat radiating pipes in communication with said drum, said interior heat radiating pipes being arranged within the drum and in transverse inclined relation with their ends mounted in the drum and extending through the walls of said drum, said exterior heat radiating pipes leading from the wall of the drum and positioned between the drum and casing, a union box to which one end of each of said exterior heat radiating pipes is connected, a stack communicating with said union box, a damper in said union box and spring means to retain said damper in normal position.

2. A warm air furnace, including a floor structure, a sectional casing supported and secured upon said floor structure, an ash pit mounted in the floor structure with an upper portion above the floor structure and a lower portion below the oor structure, a grate mounted upon the upper portion of the ash pit, in combination with a combustion chamber mounted in the upper portion of the ash pit, a drum mounted on said combustion chamber, heat circulating pipes arranged within said drum in a Vertical plane and and in inclined relation with their ends connected with the side walls of said drum, smoke conducting pipes arranged within the space between the drum and casing and disposed in a longitudinal direction with one end connected to the drum, a union box to which the other end of said pipes is connected, a damper in said union box, a pipe leading from the union box to the ash pit, a stack communicating with said drum and union box, and a damper for said stack.

JOHN O. KEEFE. 

